Icosahedral coordination of phosphorus in the crystal

American Mineralogist, Volume 91, pages 451–454, 2006
LETTER
Icosahedral coordination of phosphorus in the crystal structure of melliniite, a new
phosphide mineral from the Northwest Africa 1054 acapulcoite
GIOVANNI PRATESI,1,2 LUCA BINDI,2,3,* AND VANNI MOGGI-CECCHI1
1
Museo di Scienze Planetarie, Via Galcianese, 23-I-59100 Prato, Italy
Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy
3
Museo di Storia Naturale, Sez. di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy
2
ABSTRACT
Melliniite, ideally (Ni,Fe)4P, is a new mineral from the Northwest Africa 1054 acapulcoite. It occurs
as anhedral to subhedral grains up to 100 µm, associated with kamacite and nickelphosphide. Melliniite is opaque with a metallic luster and possesses a gray streak. It is brittle with an uneven fracture;
the Vickers microhardness (VHN500) is 447 kg/mm2 (range 440–454) (calculated Mohs hardness of
8–8½). The calculated density is 7.88 g/cm3 (on the basis of the empirical formula). In plane-polarized
reßected light, melliniite is cream-yellowish. Between crossed polars it is isotropic, with no internal
reßections. Reßectance percentages (R) for the four standard COM wavelengths are 60.5 (471.1 nm),
50.4 (548.3 nm), 52.5 (586.6 nm), and 55.9 (652.3 nm), respectively. Electron-microprobe analyses
give the chemical formula (Ni2.30Fe1.64Co0.01)Σ=3.95P1.05 on the basis of total atoms = 5.
Melliniite is cubic, space group P213, with a = 6.025(1) Å, V = 218.71(6) Å3, and Z = 4. The
crystal structure has been solved and reÞned to R = 2.72% using single-crystal X-ray diffraction data.
It shows the AlAu4-type structure, which is an ordered form of the β-Mn structure. The metal atoms
occupying the 12b site (M1) are effectively 14 coordinated whereas the metals at the 4a site (M2)
are 12 coordinated by three P atoms and nine metals. The phosphorus atoms (4a site) coordinate 12
metal atoms in a somewhat distorted icosahedral arrangement. This new phosphide is the Þrst phase
with such a high coordination-number for phosphorus.
The new mineral is named after Marcello Mellini, Professor of Mineralogy, who strongly developed
the study of meteorites in Italy. The new mineral and mineral name have been approved by the IMA
Commission on New Minerals and Mineral Names (2005-027).
Keywords: Melliniite, chemical composition, meteorites, X-ray data, new mineral
INTRODUCTION
The recent discovery that meteoritic schreibersite, (Fe,Ni)3P,
can provide enough phosphorus essential for the biomolecular
building blocks of life (Pasek et al. 2004), has drawn attention to
the study of extraterrestrial iron nickel phosphides. These minerals are fundamental constituents of iron and stony-iron meteorites
(Buchwald 1975; Geist et al. 2005; Heide and Wlotzka 1995) and
could represent the potential reservoirs of light elements in the
Earth’s core. Besides schreibersite, four other natural phosphides
are known: nickelphosphide (Ni,Fe)3P (Britvin et al. 1999; Skála
and Drábek 2003), barringerite (Fe,Ni)2P (Buseck 1969), allabogdanite (Fe,Ni)2P (Britvin et al. 2002) and ßorenskyite FeTiP
(Ivanov et al. 2000). Another P-bearing nickel-iron silicide mineral called perryite [simpliÞed chemical formula: (Ni,Fe)8(Si,P)3
with 2.4–5.2 wt% of P] is known to occur as thin lamellae within
metallic nickel-iron grains in the highly reduced stony meteorites
(Okada et al. 1988). Among these minerals, however, schreibersite is the most common phase. Recent studies (Japel et al. 2002;
Santillan et al. 2004) have pointed out that schreibersite is also
stable at ultrahigh pressures and temperatures. The wide stability range of its tetragonal structure makes this mineral the most
* E-mail: [email protected]Þ.it
0003-004X/06/0203–451$05.00/DOI: 10.2138/am.2006.2095
451
likely phase by which phosphorus was originally incorporated
in deep planetary interiors.
In the course of a study on acapulcoites, a group of primitive
achondrites (Mittlefehldt 2003; Moggi-Cecchi et al. 2005; Patzer
et al. 2004; Scott and Pinault 1999) a new nickel iron phosphide
mineral was observed.
OCCURRENCE AND METHODS
Sample
The sample containing melliniite was not found in situ, but
originates from a thin section of a meteorite (acapulcoite) belonging to the Collection of Meteorites of the Museo di Scienze
Planetarie della Provincia di Prato where it is labeled “Northwest Africa 1054” (Moggi-Cecchi et al. 2005). Acapulcoites are
peculiar primitive achondrites with transitional characteristics
from chondrites to more differentiated achondrites. Recently,
with respect to their elemental distribution patterns, Patzer et
al. (2004) distinguished four subtypes comprising primitive,
typical, transitional and enriched acapulcoites. Differently from
the other subtypes, the primitive acapulcoites, like Northwest
Africa (NWA) 1054, did not experience sulÞde melt loss and
may contain relic and scattered intact chondrules consisting of
olivine and orthopyroxene set in a matrix mainly composed of
Þne-grained orthopyroxene, olivine and plagioclase crystals.
452
PRATESI ET AL.: MELLINIITE, A NEW EXTRATERRESTRIAL MINERAL
TABLE 1. Fractional coordinates and anisotropic displacement parameters of atoms for melliniite, space group P213, a = 6.025(1) Å
x
0.11684(9)
0.6803(1)
0.0622(2)
M1
M2
P
y
0.20686(9)
0.6803(1)
0.0622(2)
z
0.45493(9)
0.6803(1)
0.0622(2)
U11
0.0295(3)
0.0261(2)
0.0242(3)
U22
0.0289(3)
0.0261(2)
0.0242(3)
Chunks of Fe-Ni metal alloys (mostly kamacite) and troilite are
the most abundant non-silicate phases. Accessory phases are
merrillite, magnesiochromite and nickelphosphide.
Melliniite occurs in the NWA 1054 acapulcoite, closely associated with kamacite (Fig. 1a) and nickelphosphide (Fig. 1b).
We have named the new mineral melliniite in honor of Marcello
Mellini, Full Professor of Mineralogy at the University of Siena,
in recognition of his contributions to the development of the study
of meteorites in Italy. Type material is housed in the Meteorite
Collection of the Museo di Scienze Planetarie della Provincia di
Prato, Prato, Italy, under catalog number MSP-2378. The new
mineral and mineral name have been approved by the IMA Commission on New Minerals and Mineral Names (2005-027).
Physical and optical properties
Melliniite shows a gray streak. The mineral is opaque in
transmitted light and exhibits a metallic luster. No cleavage is
observed and the fracture is uneven. The calculated density (for
Z = 4) from the empirical formula is 7.88 g/cm3. Unfortunately,
the density could not be measured here because of the small grain
size. Micro-indentation measurements carried out with a VHN
load of 500 g give a mean value of 447 kg/mm2 (range: 440–454)
corresponding to a Mohs hardness of about 8–8½.
In plane-polarized incident light melliniite is cream-yellowish in color. Under crossed polars melliniite is isotropic.
Internal reßections are absent and there is no optical evidence
of growth zonation.
Reßectance measurements were performed in air by means
TABLE 3. X-ray powder diffraction patterns for melliniite
1
2
Icalc
dcalc
h
k
l
3.24
3.4785
1
1
1
13.05
2.6945
2
0
1
4.27
2.4597
2
1
1
100.00 2.0083
2
2
1
35.37
1.9053
3
0
1
23.87
1.9053
3
1
0
20 1.816
1.8156
19.90
1.8166
3
1
1
5
1.609
1.6094
5.00
1.6102
3
1
2
10 1.420
1.4193
5.78
1.4201
4
1
1
10 1.348
1.3465
2.23
1.3472
4
0
2
4.14
1.3472
4
2
0
5
1.203
1.2043
2.35
1.2050
4
3
0
15 1.182
1.1810
8.35
1.1816
4
3
1
8.14
1.1816
4
1
3
5
1.160
1.1589
4.33
1.1595
5
1
1
15 1.119
1.1182
3.68
1.1188
4
3
2
5.57
1.1188
4
2
3
3.26
1.1188
5
0
2
3.66
1.1188
5
2
0
2
1.098
1.0994
2.86
1.1000
5
1
2
5
1.017
1.0179
2.57
1.0184
5
3
1
2.54
1.0184
5
1
3
2
1.003
1.0036
5.53
1.0042
4
4
2
5
0.976
0.9769
2.02
0.9774
6
1
1
2.16
0.9774
5
2
3
Notes: (1) X-ray powder-diffraction data obtained with a 114.6 mm Gandolfi
camera with Ni-filtered CuKα; (2) d values calculated on the basis of a = 6.025(1)
Å, and with the atomic coordinates reported in Table 1. Intensities calculated
using XPOW software version 2.0 (Downs et al. 1993).
I
2
15
5
100
60
dmeas
3.48
2.694
2.457
2.005
1.906
dcalc
3.4766
2.6930
2.4584
2.0072
1.9042
U33
0.0286(3)
0.0261(2)
0.0242(3)
U12
0.0001(2)
0.0004(2)
–0.0003(3)
U13
–0.0002(2)
0.0004(2)
–0.0003(3)
U23
0.0001(2)
0.0004(2)
–0.0003(3)
Ueq
0.0290(2)
0.0261(2)
0.0242(3)
of a MPM-200 Zeiss microphotometer equipped with a MSP-20
system processor on a Zeiss Axioplan ore microscope. The Þlament temperature was approximately 3350 K. An interference
Þlter was adjusted, in turn, to select four wavelengths for measurement (471.1, 548.3, 586.6, and 652.3 nm). Readings were
taken for specimen and standard (SiC) maintained under the same
focus conditions. The diameter of the circular measuring area
was 0.1 mm. Reßectance percentages (R) for the four standard
COM wavelengths are 60.5 (471.1 nm), 50.4 (548.3 nm), 52.5
(586.6 nm), and 55.9 (652.3 nm), respectively.
X-ray crystallography and crystal-structure determination
A small crystal fragment (15 × 20 × 20 µm), dug out from a polished thin
section, was selected for the X-ray single-crystal diffraction study. Unit-cell parameters, determined by centering 25 high-θ (20–25°) reßections, on an automated
diffractometer (Enraf Nonius CAD4), are a = 6.025(1) Å, V = 218.71(6) Å3, and
Z = 4. To check the possible presence of diffuse scattering or weak superlattice
peaks, the crystal was also mounted (exposure time of 150 s per frame; 40 mA ×
40 kV) on a CCD-equipped diffractometer (Oxford Xcalibur 2), but no additional
reßections were detected.
Intensity data were collected using MoKα radiation monochromatized by a ßat
graphite crystal in ω scan mode up to 2θ ≤ 75°. Intensities were corrected for Lorentzpolarization effects and subsequently for absorption following the semi-empirical
–
method of North et al. (1968). The merging R for the ψ-scan data set in the m3 Laue
group decreased from 8.65% before absorption correction to 5.24% after this correction. The analysis of the systematic absences (h00: h = 2n) together with the statistical
tests on the distribution of |E| values, that do not indicate the presence of an inversion
center (|E2 – 1| = 0.636), leads us to the choice of the space group P213.
The position of the two metal atoms (M1 and M2) was determined from the
three-dimensional Patterson synthesis (Sheldrick 1997a). A least-squares reÞnement using these heavy-atom positions and isotropic temperature factors yielded
an R factor of 14.12%. Three-dimensional difference Fourier synthesis yielded the
position of the remaining phosphorus atom. The full-matrix least-squares program
SHELXL-97 (Sheldrick 1997b), working on F2, was used for the reÞnement of
the structure. The introduction of anisotropic temperature factors for all the atoms
led to R = 2.72% for 187 observed reßections [Fo > 4σ(Fo)] and R = 2.78% for all
202 independent reßections. Because the X-ray scattering factors of Fe and Ni are
similar, it was impossible to study cation ordering in detail using X-ray data. We
choose to assign the scattering curve of Ni (i.e., the dominant cation) at the M1 and
M2 sites. Neutral scattering curves for Ni and P were taken from the International
Tables for X-ray Crystallography (Ibers and Hamilton 1974). Inspection of the
difference Fourier map revealed that maximum positive and negative peaks were
0.94 and 1.14 e–/Å3, respectively. Fractional atomic coordinates and anisotropicdisplacement parameters are shown in Table 1. Table 21 lists the observed and
calculated structure factors. Table 3 reports the X-ray powder pattern of melliniite
obtained with a 114.6 mm GandolÞ camera with Ni-Þltered CuKα.
Chemical composition
A preliminary chemical analysis using energy dispersive
spectrometry, performed on the same crystal fragment used for
the structural study, did not indicate the presence of elements (Z
> 9) other than Ni, Fe, and P and minor Co, Si, Mg, and S. The
1
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PRATESI ET AL.: MELLINIITE, A NEW EXTRATERRESTRIAL MINERAL
453
FIGURE 1. Reflected-light micrographs displaying melliniite. (a) An anhedral fragment of the new phosphide (1) associated with kamacite (2).
(b) Association of melliniite (1) and nickelphosphide (3). The image was obtained using a Zeiss Axioplan 2 microscope with AxioCam-HR Digital
Image Acquisition apparatus. Scale bars are indicated.
TABLE 4. Electron microprobe analyses for melliniite
Element
Fe
Co
Ni
Si
Mg
P
S
wt%
34.9
0.22
51.4
0.01
0.03
12.4
0.02
Range
33.9–36.6
0.08–0.24
47.0–51.5
0.00–0.04
0.00–0.07
11.6–12.4
0.01–0.05
Total
98.98
Notes: Means and ranges in wt% of elements; n = 15.
chemical composition was then determined using wavelength
dispersive analysis (WDS) by means of a Jeol JXA-8600 electron microprobe. Major and minor elements were determined at
15 kV accelerating voltage and 10 nA beam current, with a 15
s counting time. For the WDS analyses the Kα lines for all the
elements were used. The estimated analytical precision is: ±0.90
for Fe and Ni, ±0.55 for P, ±0.03 for Co, and ±0.01 for Si, Mg
and S. The standards employed were: pure elements for Fe, Co,
Ni, Si, and Mg, apatite for P, and marcasite for S. The melliniite
fragment was found to be homogeneous within analytical error.
The average chemical composition (15 analyses on different
spots), together with ranges of wt% of elements, is reported in
Table 4. On the basis of 5 atoms, the formula of melliniite is
(Ni2.30Fe1.64Co0.01)Σ=3.95P1.05, ideally (Ni,Fe)4P.
DESCRIPTION OF THE STRUCTURE AND DISCUSSION
The crystal structure of the new iron nickel phosphide shows
the AlAu4-type structure, which is an ordered form of the β-Mn
structure (a polymorph of manganese). Phosphorus occupies a
4a site and the metal atoms (i.e., Ni and Fe) a second 4a and a
12b site. This corresponds to four formula units of (Ni2.30Fe1.64
Co0.01)Σ=3.95P1.05 per unit cell. Within experimental uncertainties,
all sites are fully occupied. The crystallographic features for the
new phase are really unique for phosphorus-bearing compounds.
The metal atoms occupying the 12b site (M1) are effectively
14 coordinated whereas the metals at the 4a site (M2) are 12
coordinated by three P atoms and nine metals (Table 5). The
a3
a2
a1
a)
b)
FIGURE 2. The crystal structure of melliniite. The P atoms are
represented in red whereas the metal atoms (Ni,Fe) in white (a). The
unit cell and the orientation of the structure are indicated. Portion of the
structure of melliniite showing the twelve-coordination of phosphorus
(b). A distorted icosahedral arrangement is clearly observable.
phosphorus atoms (4a site) coordinate 12 metal atoms with
bond distances ranging from 2.247 to 2.605 Å in a somewhat
distorted icosahedral arrangement (Fig. 2). Our results show that
the new phosphide reported here is the Þrst phase with so high
a coordination-number for phosphorus. In the crystal structure
of the mineral perryite (Okada et al. 1991), there is a twelvecoordinated structural position named Si(P)1 but the dominant
cation at that site is silicon. Generally phosphorus has 9 metal
neighbors mostly in a tricapped triangular prismatic coordination
454
PRATESI ET AL.: MELLINIITE, A NEW EXTRATERRESTRIAL MINERAL
TABLE 5. Selected bond distances (Å) for melliniite
Atoms
M1–P
M2
2 M1
P
2 M1
M2
M2
2 M1
P
2 M1
Distances (Å)
2.399(2)
2.500(1)
2.496(1)
2.543(1)
2.509(1)
2.520(1)
2.531(1)
2.584(1)
2.605(1)
3.105(1)
Atoms
M2–3 P
3 M1
3 M1
3 M1
P–3 M2
3 M1
3 M1
3 M1
Distances (Å)
2.247(1)
2.500(1)
2.520(1)
2.531(1)
2.247(1)
2.399(2)
2.543(1)
2.605(1)
as in allabogdanite, (Fe,Ni)2P (Britvin et al. 2002). Rarely it can
occur as ten-coordinated as, for instance, in the synthetic Co2P
(Rundqvist 1962), but higher coordination-numbers for P atoms
are unknown in nature. On the contrary, a similar coordination
to that found here for phosphorus was observed for Si and Ge
in the recently synthesized compounds Mn3IrSi (Eriksson et al.
2004b) and Mn3IrGe (Eriksson et al. 2004a).
The new mineral melliniite represents the Þrst report of a
natural nickel iron phosphide with a metal/phosphorus ratio of
4:1. Hornbogen (1961), studying the products deriving from the
precipitation of phosphorus from alpha iron, reported a compound with chemical composition Fe4P; the crystal structure
of such Fe4P compound, however, is quite different from that
of melliniite. It consists of a face-centered lattice of iron atoms
with phosphorus at the (½, ½, ½) position. The whole lattice is
orthorhombically distorted because not all the cube centers are
Þlled with phosphorus atoms.
The calculated density for the new phase is 7.88 g/cm3 (on
the basis of the empirical formula). This value exceeds by 4%
that calculated for nickelphosphide (7.61 g/cm3), the densest
iron nickel phosphide previously known. The higher density is
more related to the metal/phosphorus ratio than to the higher
coordination of the phosphorus atoms.
Although the scarcity and the size of materials precludes additional investigations (e.g., shock wave studies, laser heating
in diamond anvil cells), we would like to speculate about the
implications of this new phase as potential candidate by which
phosphorus was originally incorporated in deep planetary interiors. The new phosphide shows a cubic symmetry, the highest
coordination-number for P atoms yet discovered, and the highest
density value for a Fe-Ni-P compound. It is well known that a
higher symmetry and atom-coordination are characteristic of a
high-pressure environment, therefore this new iron nickel phosphide could play a role for Earth’s core mineralogy.
ACKNOWLEDGMENTS
We thank F. Olmi (CNR—Istituto di Geoscienze e Georisorse—sezione di
Firenze) for his help during the electron-microprobe analyses. This work was funded
by M.I.U.R., PRIN 2003, project “crystal chemistry of metalliferous minerals” and
by the University of Florence (60% grant).
alogical Society, 128, 64–72 (in Russian).
Britvin, S.N., Rudashevsky, N.S., Krivovichev, S.V., Burns, P.C., and Polekhovsky, Y.S. (2002) Allabogdanite, (Fe,Ni)2P, a new mineral from the Onello
meteorite: The occurrence and crystal structure. American Mineralogist, 87,
1245–1249.
Buchwald, V.F. (1975) Handbook of iron meteorites, 3 vols. University of California Press, Berkeley.
Buseck, P.R. (1969) Phosphide from meteorites: Barringerite, a new iron-nickel
mineral. Science, 165, 169–171.
Downs, R.T., Bartelmehs, K.L., Gibbs, G.V., and Boisen, M.B., Jr. (1993) Interactive software for calculating and displaying X-ray or neutron powder
diffractometer patterns of crystalline materials. American Mineralogist, 78,
1104–1107.
Eriksson, T., Lizàrraga, R., Felton, S., Bergqvist, L., Andersson, Y., Nordblad, P.,
and Eriksson, O. (2004a) Crystal and magnetic structure of Mn3IrSi. Physical
Review, B69, 054422-1–054422-7.
Eriksson, T., Bergqvist, L., Nordblad, P., Eriksson, O., and Andersson, Y. (2004b)
Structural and magnetic characterization of Mn3IrGe and Mn3Ir(Si1–xGex):
experiments and theory. Journal of Solid State Chemistry, 177, 4058–4066.
Geist, V., Wagner, G., Nolze, G., and Moretzki, O. (2005) Investigations of the
meteoritic mineral (Fe,Ni)3P. Crystal Research Technology, 40, 52–64.
Heide, F. and Wlotzka, F. (1995) Meteorites—Messengers from Space, 231 p.
Springer-Verlag, Berlin.
Hornbogen, E. (1961) Precipitation of phosphorus from α-iron and its effect on
plastic deformation. Transactions of the American Society for Metals, 53,
569–589.
Ibers, J.A. and Hamilton, W.C., Eds. (1974) International Tables for X-ray Crystallography, vol. IV, 366 p. Kynock, Dordrecht, The Netherlands.
Ivanov, A.V., Zolensky, M.E., Saito, A., Ohsumi, K., Yang, S.V., Kononkova, N.N.,
and Mikouchi, T. (2000) Florenskyite, FeTiP, a new phosphide from the Kaidun
meteorite. American Mineralogist, 85, 1082–1086.
Japel, S., Prewitt, C.T., Boctor, N., and Veblen, D. (2002) Iron-nickel phosphides at
high pressures and temperatures. AGU Fall Meeting, abstract MR61A-1025.
Mittlefehldt, D.W. (2003) Acapulcoite-Lodranite Clan Achondrites—How many
parent bodies? Meteoritics and Planetary Science, 38, A95.
Moggi-Cecchi, V., Pratesi, G., and Mancini, L. (2005) NWA 1052 and NWA 1054:
two new primitive achondrites from North West Africa. XXXVI Lunar and
Planetary Sciences Conference, abstract 1808.
North, A.C.T., Phillips, D.C., and Mathews, F.S. (1968) A semiempirical method
of absorption correction. Acta Crystallographica, A24, 351–359.
Okada, A., Keil, K., and Taylor, G.J. (1988) Igneous history of the aubrite parent
asteroid: evidence from the Norton County enstatite achondrite. Meteoritics,
23, 59–74.
Okada, A., Kobayashi, K., Ito, T., and Sakurai, T. (1991) Structure of synthetic
perryite, (Ni,Fe)8(Si,P)3. Acta Crystallographica, C47, 1358–1361.
Pasek, M.A., Smith, V.D., and Lauretta, D.S. (2004) Meteorites as a supplement
and/or source of phosphorus for the origin of life. Abstracts of Papers of the
American Chemical Society, 228: 034-Geoc Part I.
Patzer, A., Hill, D.H., and Boynton, W.V. (2004) Evolution and classiÞcation of
acapulcoites and lodranites from a chemical point of view. Meteoritics, 39,
61–85.
Rundqvist, S. (1962) Binary transition metal phosphides (and crystal-chemical
relations between them and transition metal compounds with other nonmetals
of small atomic radius). Arkiv foer Kemi, 20, 67–113.
Santillan, J.D., Williams, Q., and Scott, H.P. (2004) The equation of state of Fe3Piron phosphide to 54 GPa. AGU Fall Meeting, abstract MR11A-0912.
Scott, E.R.D. and Pinault, L.J. (1999) Partial Melting and Incipient Segregation
of Troilite and Metal in Winonaites, Acapulcoites, IAB and IIE Irons, and
Fine-Grained H6 Chondrites. XXX Lunar and Planetary Science Conference,
Houston, abstract 1507.
Sheldrick, G.M. (1997a) SHELXS-97. A program for automatic solution of crystal
structures. University of Göttingen, Germany.
——— (1997b) SHELXL-97. A program for crystal structure reÞnement. University of Göttingen, Germany.
Skála, R. and Drábek, M. (2003) Nickelphosphide from the Vicenice octahedrite:
Rietveld crystal structure reÞnement of synthetic analogue. Mineralogical
Magazine, 67, 783–792.
REFERENCES CITED
Britvin, S.N., Kolomensky, V.D., Boldyreva, M.M., Bogdanova, A.N., Kretser,
Yu.L., Boldyreva, O.N., and Rudashevskii, N.S. (1999) Nickelphosphide,
(Ni,Fe)3P, the nickel analog of schreibersite. Proceedings of Russian Miner-
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